Resins for Rapid Manufacturing of C-C Composites

Carbon-carbon composites (C/C) are currently used as hot structures in a variety of extreme environments encountered during rocket launch, hypersonic flight, and atmospheric entry, descent and landing. Their use is limited by their expensive and time-consuming manufacturing process. Delivery times of over six months from order placement are common, a result of the long manufacturing process and the limited number of suppliers. Building on our demonstrated expertise in carbon manufacturing and commercialization, in this Phase II project we will develop manufacturing capability for a novel resin so that C/C composites can be made in days to weeks, instead of months. This resin has the potential to eliminate multiple densification cycles, yet result in composites with equivalent mechanical and thermal properties to the current state-of-the-art. With the domestic need for C/C parts increasing, TDA believes that there is a currently an outstanding opportunity to enter the C/C manufacturing market. TDA has a demonstrated history of manufacturing resins with high char yields, and we propose to build on that experience to economically manufacture resins that have been demonstrated to produce strong chars in exceptionally high yield. TDA Research, Inc. (TDA) proposes a two-step manufacturing process for carbon fiber – carbon matrix (“C/C”) composites suitable for use as hot structures on a wide variety of aerospace vehicles subject to extreme aerothermal heating. A carbon black-filled high char yield polymer made at TDA will be used to achieve a density exceeding 1.5 g/cc after carbonization and 1.6 g/cc after graphitization. The key to our approach is an economical synthesis for the polymer, whichhas a char yield of 80%, much higher than the 60% or so achieved by the phenolic resins currently used for C/C densification. By avoiding multiple resin infiltration steps, the production of C/C will be considerably more rapid than is currently practiced, and the resulting C/C products more uniform. The overall goal of this project is to develop a resin from which C/C can be rapidly and cost-effectively manufactured, where the properties of the resulting C/C are at least equivalent to the current commercial standard. In Phase II, we will specifically focus on the development of C/C nozzle extensions. There are six Phase II Technical Objectives: TO-1: Demonstrate a cost-effective synthesis for the key monomer in high yield. TO-2: Optimize the cure cycle for the resin so that cured coupons with a polymer matrix and woven carbon fiber reinforcements have essentially no residual porosity TO-3: Using our resins, demonstrate densification of C/C composites, so that high density is obtained with one or two re-infiltrations. TO-4: Demonstrate that key mechanical and thermal properties of our C/C are essentially par (or better) than those of a commercial standard that is widely used for nozzle extensions. TO-5: Manufacture axisymmetric conical C/C products from carbon fiber cloth and our resins TO-6: Manufacture C/C nozzle extensions that are a few inches in diameter, and with an integrated attachment feature. At the conclusion of the Phase II project, TDA will deliver two nozzle extensions of C/C made with BODA resin for evaluation at NASA.
Benefits: The proposed resin system will be used for rapid manufacturing of high quality C/C hot structures. Our initial target application will be lightweight nozzle extensions for in-space propulsion systems, Lunar/Mars ascent/descent vehicles, and upper stage rocket engines. Subsequent applications may include nuclear thermal rockets, hot gas valves and hypersonic combustors/aeroshells. TDA’s process will shorten development and procurement schedules, thereby providing substantial cost savings to all programs that utilize our C/C. Several DoD agencies, including the Air Force, Navy, Army, and Missile Defense Agency (MDA) would benefit from improved C/C manufacturing for their launch and hypersonic vehicle programs, which make extensive use of C/C hot structures as acreage panels and in the combustor. C/C parts are also of interest to gas turbine manufacturers like General Electric.